This device utilizes ultrasonic sound waves to create a feeling of nauseousness in any humans within auditory range.
It has a standard effective range of approximately 10 meters.
It uses a high frequency oscillator to produce ultrasonic electrical waves that are amplified by transistors and converted to sound waves by a high frequency responsive speaker powered by only a 9 Volt battery.
The reason it works is very simple. The ultrasonic waves travel through the ear canal and pass through a region very close to the human equilibrium. The waves are such a high frequency that they cause resonance in the ear canal and it begins to severely vibrate the equilibrium, causing the sediment–filled liquid to slosh around a bit.
It is this that causes a feeling of disorientation and quickly makes the victim(s) feel the sudden urge to vomit. It also causes dizziness, temporary vision problems, and possible mental disorders after prolonged exposure.
Learn more about how the Sonic Nausea Generator works.